The present invention relates to vehicle closure element latches and more particularly, to a cinching mechanism for associating with a latch to provide a motive force in automatically driving the door latch between operative positions.
It is known to provide a cinching mechanism for power operation of a latch to assist vehicle users in closing a door, hatch or similar component (referred to in the aggregate as closure elements), against weather seal pressure. A primary consideration is that power driving a closure element through its final pivoting motion to a fully closed position is opposed by a considerable force. This force arises due to a need to compress a weather seal interposed between the closure element and the vehicle body in addition to the possible presence of such features as rubber bumpers serving to reduce rattling between the closure element and the vehicle body.
The prior art has generally developed functional mechanisms for power driving a latch, one of which is disclosed in U.S. Pat. No. 4,763,936 entitled "Power Operated Door Latch" which issued Aug. 16, 1988. This type of device entails redesigning the latch assembly itself in order to incorporate the power drive mechanism.
It has been found that it is preferable to design a cinching mechanism which can be incorporated with a standard latch assembly with minimal changes thereto. A complicating factor in providing such a cinching mechanism is the fact that the latch will preferably continue to operate in a manual mode in addition to a power mode.